Plug-n-play power system for an accessory in an aircraft

ABSTRACT

A power system for an aircraft. The power system comprises a power module unit and at least one mounting rail detachably coupled to the power module unit. The mounting rail provides structural support and electrical power to the power module unit. A power system in one embodiment may use mounting rails that double as power rails supplying power to the power module unit. Control is accomplished over a wireless link. The power rail control may be accomplished remotely via a standard or solid state relay. Normal rail power for the rail mounted power module may come from the utility bus.

FIELD OF THE INVENTION

The present invention relates generally to an aircraft and morespecifically to a power system for accessories in the aircraft.

BACKGROUND OF THE INVENTION

In today's commercial airplanes, a power system for accessories such aslaptop or notebook computer has complex power, delivery and discretewiring, and is difficult to install. When a power system unit needs tobe moved or replaced, it can take several minutes to accomplish the jobbased upon the complexity of the system. When this move or replace isassociated with a seat repitch or retrofit within the aircraft, a greatdeal of time can be lost. Accordingly, it is desired to provide for theinstallation and removal of power system for accessories without thedifficulties and time loss associated with the conventional overheadvideo passenger service.

Accordingly, what is needed is a system and method for providing asimple, lightweight and reliable power system unit in an aircraft. Thepresent invention addresses such a need.

SUMMARY OF THE INVENTION

A power system for an aircraft is disclosed. The power system comprisesa power module unit and at least one mounting rail detachably coupled tothe power module unit. The mounting rail provides structural support andelectrical power to the power module unit.

A power system in one embodiment may use mounting rails that double aspower rails supplying power to the power module unit. Control isaccomplished over a wireless link. The power rail control may beaccomplished remotely via a standard or solid state relay. Normal railpower for the rail mounted power module unit may come from the utilitybus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic diagram of a cabin services system inaccordance with a number of embodiments.

FIG. 2A illustrates a block diagram of a cabin services system inaccordance with one of the embodiments.

FIG. 2B illustrates a block diagram of an alternate embodiment of acabin services system in accordance with one of the embodiments.

FIG. 2C illustrates one implementation of the cabin attendant panel.

FIG. 3 is a diagram that illustrates the operation of passenger serviceunit mounting rails with circuits connected thereto.

FIG. 4 is an example of a simplified wireless overhead electronics unit.

FIG. 5 is a perspective view of a portion of a passenger service unitmodule.

FIG. 6A is a view of an embodiment of a power system.

FIG. 6B is a block diagram of one embodiment of a power module unit.

FIG. 6C is a block diagram of another embodiment of a power module unit.

FIG. 7A is a detailed view of the power module unit of FIG. 6B.

FIG. 7B is a detailed view of the power module of FIG. 6C.

FIG. 8 is a block diagram of the embodiment of a power switching systemfor use with the power module unit.

DETAILED DESCRIPTION

The following description is presented to enable one of ordinary skillin the art to make and use the invention and is provided in the contextof a patent application and its requirements. Various modifications tothe preferred embodiments and the generic principles and featuresdescribed herein will be readily apparent to those skilled in the art.Thus, the present invention is not intended to be limited to theembodiments shown, but is to be accorded the widest scope consistentwith the principles and features described herein.

A method and system in accordance with a number of embodimentsstreamlines the process for installation and removal of a one or morepower units over conventional power module units. These embodiments maybe utilized in conjunction with a rail system within an aircraft forproviding power to the power module unit. In so doing, a system isprovided that may allow for a power unit to be easily installed andremoved. U.S. patent Ser. No. 11/303,498 entitled “Simplified PowerSystem for a Cabin Services System for an Aircraft”, filed on Dec. 16,2005 and assigned to the assignee of the present application, describeda power rail system in accordance with a number of embodiments and isincorporated by reference in its entirety herein. The embodiment of thepower module unit is described in the context of a cabin services unit;however, one of ordinary skill in the art readily recognizes that avariety of cabin services units could be utilized within the spirit andscope of the present invention. Therefore, the following description isutilized to describe with particularity the features of the describedembodiment, but in no way limited by the embodiments.

A cabin services system 100 according to a number of embodiments isillustrated in FIG. 1. The cabin services system 100 may include aplurality of wireless networks 102. Each of the wireless networks 102may transmit and receive passenger services commands. Each of thewireless networks 102 may be preferably associated with a seat group.The cabin services system 100 may further include wireless passengercontrol units 202 a-202 n, passenger service units 204 a-204 n, aplurality of cabin zone units 114, a cabin control unit (not shown) anda cabin attendant panel 112. Each passenger control unit 202 a-202 n maytransmit cabin services system commands to a corresponding passengerservice unit 204 a-204 n. Each passenger service unit 204 a-204 n mayinclude a wireless receiver (not shown) and a controller (not shown)which are used to control passenger service unit functionality. Thecabin services system 100 may further include a passenger service unitpower rail (not shown) which is integrated with a passenger service unitmounting rail (not shown) to provide electrical power to each passengerservice unit 204 a-204 n. Finally, individual personal air outlet fansmay be installed in each passenger service unit 204 a-204 n to eliminateflex hose hookups that are typically required in conventional cabinservices systems.

Additionally, systems may be greatly simplified, passenger controls maybe more easily reached by passengers, and each passenger service unit204 a-204 n may be quickly installed and maintained without any wiringor duct hookups.

Similarly, wireless interfaces may be used to provide data or control ofother passenger service unit module functions. For example, videomonitors mounted onto a passenger service unit may receive video datawirelessly via a cabin wireless network. Also, passenger signage can becontrolled (turned on/off or fed content for display) via a wirelessinterface.

Taken together, these wireless interfaces allow for the elimination ofwiring to passenger service unit modules. This leaves electrical poweras the electrical interface to each passenger service unit module viathe passenger service unit mounting rails themselves and also provides ameans for powering non-essential or essential loads on these rails. Inone implementation, the passenger service unit mounting rails areenergized with electricity such that when a passenger service unitmodule is clipped to the mounting rail, electrical contact is also madebetween the passenger service unit module and the mounting rail toprovide electrical energy to the passenger service unit module.

The powered passenger service unit rail system is comprised of thefollowing components:

Airplane Wiring

Airplane wiring may consist of four wires:

-   -   Two non-essential power wires (typically 115 VAC and current        return)    -   Two essential power wires (typically 28 VDC and current return)        Stow Bin Assembly

A typical commercial stow bin assembly consists of a housing assemblythat supports a stow bin, passenger service unit mounting rails andother equipment.

Simplified Overhead Electronics Unit (SOEU)

The simplified overhead electronics unit (SOEU) for the embodimentperforms three functions:

-   -   Convert power inputs into a “safe-to-touch” power output (such        as 12V DC)    -   Switch the outputs from being powered by the non-essential power        input to being powered by the essential power input whenever the        essential bus becomes live    -   Reversing the polarity of the outputs when the essential bus        becomes live

Note that the simplified overhead electronics unit must perform itsfunctions while maintaining circuit separation between the non-essentialand the essential busses at all times.

To describe the features of the present embodiment in more detail refernow to the following description in conjunction with the accompanyingfigures.

Cabin Services System (CSS)

In one embodiment, a cabin services system 100′ may include a cabincontrol unit 113 wired to a cabin attendant panel 112′ as shown in FIG.2A. The cabin control unit 113 may be wired to a plurality of cabin zoneunits 114. The cabin zone units 113 may in turn communicate wirelesslyto a plurality of wireless seat group networks 115. Each wireless seatgroup network 200 may include a plurality of passenger control units 202a-202 n that communicate wirelessly with one passenger service unit 204.In this method, data from the cabin attendant panel 112′ may be relayedby wiring to the cabin zone unit 114′ data and may be transmitted by thecabin zone unit 114′ wirelessly to the passenger service unit 204. Thewiring from the cabin attendant panel 112′ to cabin zone unit 114′ mayexist for functions other than passenger service functions, (such asgeneral cabin lighting control, cabin air temperature data, zonalattendant call light control and many other functions not related to thepassenger service functions) thereby eliminating the need to add extrawire or wireless radio hardware for the cabin attendant panel 112′ topassenger service unit 204′ communication.

FIG. 2B illustrates a block diagram of an alternate embodiment of acabin services system 100″. The cabin services system 100″ may include awireless cabin attendant panel 112″ that may communicate wirelessly witha plurality of wireless seat group networks. A wireless seat groupnetwork 200 may include a plurality of passenger control units202′a-202′n that may communicate wirelessly with a passenger serviceunit 204′. This method may allow small commercial aircraft to performcabin services functions normally found on large commercial aircraft.Further, the wireless cabin attendant panel 112″ may wirelessly transmitcommands to a plurality of other airplane components in order to controlfunctions such as general cabin lighting, zonal attendant call light,and record cabin air temperature data. Each of the components listedabove may be wirelessly enabled to afford this functionality.

Passenger Service Unit (PSU) 204

The passenger service unit 204 may comprise a wireless receiver 206, acontroller 208, memory 210, reading lights 212 a-212 n, a flightattendant call light 214, a flight attendant call cancellation switch216, personal air outlets 218 a-218 n, and a reed switch 220. Thefeatures of each of these components are described in more detail inconjunction with the accompanying figures hereunder.

The wireless passenger control unit transmitter 202 may allow forcommunication with the passenger service unit 204 without an in-flightentertainment system or any other wires. Thus, the cabin services systemis not reliant on an in-flight entertainment system and an aircraft canbe built without a conventional in-flight entertainment system. Thisallows airlines to choose not to install wired in-flight entertainmentsystems (which significantly reduces weight) or to use the latestportable in-flight entertainment systems, such as the digEplayer oreXpress, on widebody aircraft.

A passenger control unit including the wireless passenger control unittransmitter 202 may be installed anywhere in the passenger seat (seatarm, seat back, etc.) within easy reach of the passenger. Wirelesspassenger control unit transmitters 202 may be battery powered, or mayuse energy harvesting for power without batteries. An energy harvestingwireless passenger control unit transmitter may be constructed, forexample, by integrating an EnOcean piezoelectric or electrodynamicwireless transmitter (www.enocean.com, part numbers PTM100 or PTM200)into a passenger control unit such that passenger actuation of thepassenger control unit control buttons closes a specific control switchon the EnOcean transmitter and depresses the energy bar, thus resultingin wireless transmission of command telegrams from the passenger controlunit to a receiver (for example, an EnOcean receiver—EnOcean P/N RCM120) mounted in the passenger service unit. The command telegrams mayinclude an identifier unique to the transmitter and indication of whichcontrol switch was closed at the time of pressing the energy bar.

Passenger Service Unit (PSU) Functionality

Passenger service unit modules may come in many forms. Any givenpassenger service unit module may include one or more of the followingfunctionalities:

-   -   Flight attendant call light    -   Reading light    -   Personal air outlets    -   Emergency oxygen    -   In-flight entertainment system control such as video or audio        channel selection    -   Cabin signage such as “fasten seat belt”, “no smoking” or other        passenger information

It should be understood by one of ordinary skill in the art that avariety of other functions could be included and their use would bewithin the spirit and scope of the present embodiment.

In one embodiment, each passenger service unit may utilize the followingfeatures to allow it to easily snap onto a mounting rail in an aircraftwithout wire, duct or tube hookups: a 12V DC powered mounting rail,wireless technology, and fans mounted onto a passenger service unit.

Powered mounting rail: the passenger service unit mounting rail providesboth a structural interface for installing a passenger service unit aswell as an electrical power interface. Each passenger service unit maysimply snap onto the mounting rail for both mechanical attachment andfor electrical power.

Wireless technology: together, the wireless passenger control unit,wireless interface to the cabin attendant panel and the passengerservice unit power rail (or power line) within the mounting rail mayeliminate the need to hook up wires to a passenger service unit.

Fans mounted onto a passenger service unit: ducting for a personal airoutlet and hookup to each passenger service unit may be replaced byindividual personal air outlet fans built into each passenger serviceunit. This results in less noise (compared to high pressure ducting andnozzles of a conventional personal air outlet).

The reading light, flight attendant call, nozzles and fans of a personalair outlet and emergency oxygen may be assembled in an integratedpassenger service unit module that snaps onto the mounting rail withoutany wire or duct hookups.

In one implementation, fans (mounted onto a passenger service unit) maydraw “fresh” air into a passenger service unit plenum through an inletgrill located adjacent to the cabin air distribution nozzles. In such animplementation, ducts of a personal air outlet may be eliminated andcabin noise may be reduced.

In one implementation, oxygen masks may be deployed by turning off powerto a utility bus on the passenger service unit mounting rail andmomentarily turning on an essential power bus and reversing electricalpolarity on a power rail within the passenger service unit mountingrail. Current will then flow through a diode in the oxygen circuit toactivate the mask drop solenoid.

Cabin Attendant Panel (CAP)

FIG. 2C illustrates one implementation of the cabin attendant panel 112.The wireless cabin attendant panel 112 may be used to transmit wirelesscontrol signals via control button 402 directly to groups of passengerservice units for functions such as turning on/off passenger signage(e.g., “No Smoking”, “Fasten Seat Belt”, etc.), and for resetting thepassenger service units via reset button 404 during gate turnaroundbetween flights (e.g., turning off all reading lights, personal airoutlets, and flight attendant call lights; and turning on all “NoSmoking” and “Fasten Seat Belt” signs). In this manner, the cabincontrol unit and cabin zone module may be bypassed, greatly simplifyingthe system architecture.

In a preferred implementation of the cabin attendant panel, the cabinattendant panel may make use of other aircraft wireless transmitterslocated in various positions in the airplane to relay its controlsignals to the seat group networks. These other wireless transmitterscan include a wireless function added to the cabin zone modules (part ofthe cabin services system). In this case, the cabin attendant panel maybe part of a wired or wireless network common to these zone controlelectronic boxes. It may also be part of other aircraft systems, such asa wireless cabin network. The cabin attendant panel can further includea display (not shown) for displaying data (e.g., prognostic data) to amechanic or flight personnel, as described in greater detail below.

Passenger Service Unit (PSU) Mounting Rails

FIG. 3 is a diagram that illustrates the operation of the passengerservice unit mounting rails with passenger service unit circuits asindicated by loads 403 a, 403 b and 403 c connected thereto. As is seen,under normal operating conditions, a diode 402 in series with eachpassenger service unit module circuit allows current to flow throughnon-essential circuits 408. Non-essential circuits are, for example,circuits for in-flight entertainment monitors, reading lights and flightattendant call lights. For essential circuits 410, such as one foroxygen deployment, a diode 404 in series prevents current from flowinginto the circuit. Thus, under non-normal operating conditions, such asduring emergency oxygen deployment, the output of the wireless overheadelectronics unit 406 reverts from a non-essential power mode to anessential power mode and the output polarity is reversed. Thus, thediodes 402 on the non-essential circuits prevent current to flow throughthem while the diodes 404 on the essential circuits now allow current toflow through them. This can be used, for example, to momentarily power asolenoid that opens an oxygen mask door thus allowing oxygen masks tofall into the cabin, or, for example, to continuously power a wirelesslyactivated oxygen system.

Note that if a circuit 412 requires power during both normal andnon-normal conditions, diodes may be used to provide power to thecircuit 412 under either condition. Also note that if the circuit 412could operate with either polarity, no diodes would be necessary and thecircuit may be connected to each of the rails.

In one implementation, the 12V DC mounting rail contact and the currentreturn contact may be widely spaced. In this implementation, such adesign helps to prevent accidental shorting across the contacts with,e.g., a conductive tool that might otherwise startle a mechanic bydischarging sparks. Additionally, all portions of the passenger serviceunit mounting rails that cannot be contacted by the electrical contactof the passenger service unit may be made from non-conductive materialsor finished with non-conductive finishes as another preventive measureagainst accidental shorting.

The passenger service unit power rail may implement any low voltagepower type, AC or DC. Many power rail designs other than that shown inFIG. 3 are feasible. For example, the male spring contact may be movedto the passenger service unit with the female contact inserted into agroove in the mounting rail arm. In this case, both the 12V DC mountingrail contact and current return contact may be located on the same sideof the passenger service unit (instead of opposite sides) since bothmounting rail contacts can be recessed protecting them from accidentalshorting with, e.g., a conductive tool.

FIG. 4 is an embodiment of a simplified overhead electronics unit (SOEU)400. As is seen, a power panel 402 provides power to the simplifiedoverhead electronics unit 406 via a non-essential power bus 404 and/oran essential power bus 406. In this embodiment the non-essential powerbus 404 may be 115 VAC and the essential power bus 406 may be 28 VDC.The simplified overhead electronics unit 400 may include a firstconverter 408 for converting the essential voltage from in thisembodiment 28 VDC to 12 VDC and a second converter 410 for convertingthe essential voltage bus from 115 VAC to 12 VDC. The simplifiedoverhead electronics unit 406 may be typically mounted on the stow binassembly. In this example, only power from the non-essential power businputs are being used to create the 12 VDC output under normal operatingconditions (when the essential bus 406 is not live). When the essentialpower bus 406 becomes live, a relay may be energized to switch theoutput from being driven by the non-essential power bus 404 to beingdriven by the essential power bus 406 input. Note that the outputpolarity will be reversed relative to the normal operating conditionwhen this occurs.

In this example:

The non-essential power bus 404 may be 115 VAC and may be transformed to12 VDC by an AC-to-DC converter 610 within the simplified overheadelectronics unit 400.

The non-essential power bus 404 may also be turned off without turningon the essential power bus 406 by opening a circuit breaker or relay,typically located in a power panel.

The essential power bus 406 may be 28 VDC and may be converted to 12 VDCby a DC-to-DC converter 608 within the simplified overhead electronicsunit 400.

The essential power bus 406 may typically be turned on via a relaytypically located in a power panel. The relay may, for example, beactivated by a switch 412 in the Flight Deck, such as for emergencyoxygen deployment.

The power buses may be fed through the simplified overhead electronicsunit 406 for installation convenience. This may allow several simplifiedoverhead electronic units 400 to be daisy chained together down theairplane.

There are several ways to accomplish the simplified overhead electronicsunit 400 functionality. The example circuit shown in FIG. 4 is just oneway to implement this function.

Passenger Service Unit Mounting Rail

FIG. 5 is a perspective view of a portion of the passenger service unitmodule 300. The portion of the passenger service unit module 300illustrated in FIG. 5 shows an electrical contact assembly 301. Theassembly 301 may comprise an electrical spring contact 302 and aplastic, non-conductive, insulating support 304. The electrical springcontact 302 may be made of, for example, beryllium copper that is nickeland gold plated. The electrical spring contact 302 may be designed toclip onto the round portion of electrically conductive passenger serviceunit mounting rail 306. The plastic support 304 may be also designed toclip onto the passenger service unit mounting rail 306 and may beintended to support the electrical spring contact 302 and to prevent theelectrical spring contact 302 from rocking back and forth on thepassenger service unit mounting rail 306. The electrical contactassembly 301 may be loosely fastened to a passenger service unit modulesuch that when a passenger service unit module vibrates under thepassenger service unit mounting rail 306, the electrical spring contact302 will float over the passenger service unit module and maintain itsgrip on the passenger service unit mounting rail 306. With theseelements in place, the electrical spring contact 302 may mate with theelectrically conductive portion of the passenger service unit mountingrail 306 when the passenger service unit is installed and held in placeby the passenger service unit catches (not shown).

Accordingly, each passenger service unit module 300 may receiveelectrical power from the mounting rail 306 via its electrical springcontacts 302.

Passenger service unit mounting rails may be typically constructed froman aluminum extrusion that is approximately the same length as the stowbin assembly. In this embodiment the mounting rails may have thefollowing features:

Each rail may be electrically connected to one of the outputs from thesimplified overhead electronics unit 406 via a wire. Thus, one rail maybe connected to the normally positive DC output and the other rail maybe connected to the normally negative DC output.

The edge of the rail that passenger service unit module clips may attachto is kept electrically conductive. While most surfaces of the rail aretypically primed and painted, the aluminum rail along this edge may beplated, for example, with nickel and gold to provide electricalconduction.

Note that the simplified overhead electronics unit above may energizethese rails with 12 VDC voltage.

In a system and method in accordance with the present embodiment thepassenger service unit mounting rails may perform two functions:

(1) Mechanical support of the passenger service unit modules; and

(2) Electrical supply to the passenger service unit modules.

This may minimize the addition of new components or weight to theairplane. However, because of this dual functionality, electricalisolation may be required between the rail and any adjacent conductiveairplane parts. Thus, plastic bushings may likely be used at the railmounting points.

When combined with a wireless data infrastructure, the mounting railsmay greatly simplifies the passenger service unit installation byproviding electrical power to passenger service unit modules via thepassenger service unit mounting rails instead of through electricalwiring. With no data or power wiring interfaces, passenger service unitmodules may be able to be installed, removed or relocated much morerapidly.

Power Module Units

FIG. 6A is a view of one embodiment of a power system 600. In thissystem, a power panel may be mounted on structural bin rails that doubleas power rails 601. The rails 60 I provide power to the power moduleunit 604. Current limiting and short circuit protection may be providedby a power module unit power supply.

FIG. 6B is a block diagram of one embodiment of a power module unit 602.FIG. 7A is a detailed view of the power module unit 602 shown in FIG.6B.

Referring to FIG. 7A, power supply 606 a may provide power conditioningto the three power outlets 608 a-c limiting the current sourced to eachoutlet to a predetermined current such as 1.5 A. In this embodiment, thethree power outlets may provide 12 VDC.

FIG. 6C is a block diagram of another embodiment of a power module unit604. FIG. 7B is a detailed view of the power module 604.

Referring to FIG. 7B, the power supply 606 b may provide power to apower outlets 610 limiting the current source to a predetermined currentsuch as 1.5 A. In this embodiment, the power supply may provide powerconditioning and 60 HZ power inversion to provide a standard 115 VACpower outlet.

In both FIGS. 7A and 7B, the passenger service unit power supply mayobtain their power from the powered rails. That power is thenconditioned by the passenger service unit power supply 606 a and 606 band distributed to the individual automotive or defined powerconnectors. Accordingly, the power supply may provide power to anaccessory portable device on the aircraft such as a laptop computer,notebook computer, personal digital assistant, portable phone, MP3player, IPOD or the like.

FIG. 8 is a block diagram of the embodiment of a power switching system800 for use with a power module unit 802 in accordance with a number ofembodiments. The power switching system 800 may utilize a relay 808(either a mechanical or a solid state). Since the power module unit 802may share the power rails 306 a-306 b with the oxygen passenger serviceunit (not shown), each power module unit 802 may be protected by diode812 to prevent power from being applied to the power system 802 whileoxygen may be deployed.

In this system, the power rails 306 a-306 b may also double as theoxygen mask deploy wiring. The oxygen deploy discrete output 804 may betied to the relay coil 808. When oxygen is commanded, the relay 808 maybe energized and 12 VDC power from the primary bus may be routed to thepower rails 306 a-306 b in reverse polarity causing the oxygen passengerservice unit door solenoid 806 to be energized causing the oxygen masks(not shown) to deploy. The diode 812 in the power module unit 802 maykeep the power system off until utility bus power is restored and theoxygen discrete is returned to its normal state. The details of oneembodiment of an oxygen deployment system are described, for example, inU.S. patent Ser. No. 11/303,498 entitled “Simplified Power System for aCabin Services System for an Aircraft”, filed on Dec. 16, 2005, assignedto the assignee of the present embodiment, and incorporated by referenceherein.

OTHER EMBODIMENTS

Many other embodiments of this system are possible:

In addition, separate power rails may be added to the stowage binassembly, parallel to the passenger service unit mounting rails, inorder to provide the electrical power function.

This system does not rely on wireless data communication to thepassenger service unit modules. Other communication options may includetraditional wires or communications over power line (COPL) technologies.

Circuits that need to operate when power is completely shut off from therails may include a battery or capacitor that is charged via the railsduring normal operation.

The power rail may use any of low voltage power type, AC or DC. Manypower rail and electrical contact designs other than that shown in FIG.5 are feasible.

Accordingly, a system and method in accordance with the embodimentprovides an overhead video system that is integrated with a passengerservice unit power rail to provide a modular system. As a result, theoverhead system can be installed and replaced in an efficient fashion.

Although the present embodiment has been described in accordance withthe embodiments shown, one of ordinary skill in the art will readilyrecognize that there could be variations to the embodiments and thosevariations would be within the spirit and scope of the presentembodiment. For example, implementations of a cabin services systemdescribed above can be implemented in any type of commercial vehiclesincluding, e.g., helicopters, passenger ships, automobiles, and so on.Accordingly, many modifications may be made by one of ordinary skill inthe art without departing from the spirit and scope of the appendedclaims.

What is claimed is:
 1. A passenger services system for a vehicle,comprising: a passenger service unit to communicate wirelessly with acabin attendant panel and provide a plurality of cabin services; apassenger control unit to communicate wirelessly with the passengerservice unit and each including a plurality of switches corresponding tothe plurality of cabin services; an electrical spring contact; at leastone power system to provide power to the passenger services system, theat least one power system comprising a power module unit; and at leastone mounting rail to provide both structural support and electricalpower to the power module unit and to the passenger service unit,wherein the passenger service unit is coupled to the electrical springcontact that detachably clips to the at least one mounting rail, theelectrical spring contact providing both structural support to thepassenger service unit and a spring coupling to the at least onemounting rail, wherein the electrical spring contact is coupled to thepassenger service unit by a non-conductive insulating support that clipsonto the mounting rail and provides electrical isolation from thepassenger service unit.
 2. The passenger services system of claim 1wherein the at least one power system comprises: a simplified overheadelectronics unit (SOEU); a first electrical circuit coupled to themounting rail and the SOEU for allowing operation of essential functionswhile electrically connected to the mounting rail; and a secondelectrical circuit coupled to the mounting rail and the SOEU forallowing operation of the at least one power system while electricallyconnected to the mounting rail, the at least one power system providingpower for operation of non-essential functions.
 3. The passengerservices system of claim 2 wherein the first electrical circuit and thesecond electrical circuit operate alternately based upon a polarity ofthe power of the mounting rail.
 4. The passenger services system ofclaim 3 wherein the first electrical circuit and the second electricalcircuit operate concurrently.
 5. The passenger services system of claim3 wherein the SOEU utilizes a discrete signal to trigger a reversal ofthe polarity of the power of the mountina rail.
 6. The passengerservices system of claim 5 wherein the SOEU provides power to an oxygenpassenger service unit module.